Ammonia Concentrations Over Europe – Application of the WRF-Chem Model Supported With Dynamic Emission

The study focuses on the application of a static and dynamic ammonia emission based on a Europe-wide default setting into the Weather Research and Forecasting Chemistry model (WRF-Chem) and the influence on the simulated ammonia concentrations and the overall model performance. The WRF-Chem model was run twice for the entire Europe at a spatial resolution of 36 x 36 km for the year 2012. In the first simulation we used a static emission approach (the “BASE” simulation), whereas in the second simulation, dynamic ammonia emissions were used (the “DYNAMIC” simulation). Both simulations underestimate measured concentrations of NH3 for all seasons, have similar NMGE (about 0.7 μg m-3) and modelled hourly ammonia peaks are shifted towards the afternoon hours if compared with measurements. However, for all temporal resolutions, normalised mean gross error in winter and summer is lower for DYNAMIC than for BASE. The DYNAMIC simulation also generally gives worse performance in spring for each temporal resolution. For further improvement of the modelled ammonia concentrations with WRF-Chem we suggest to use a nested approach with higher spatial resolution, which will lead to better separation of the ammonia source regions from surrounding areas, and take into account national practice and regulations in the emission model, eventually only in the nested model domain

Spatial, Temporal and Vertical Distribution of Ammonia Concentrations Over Europe – Comparing a Static and Dynamic Approach With WRF-Chem

The study focuses on the application of a dynamic ammonia emission into the Weather Research and Forecasting Chemistry model (WRF-Chem) and the influence on the simulated ammonia concentrations and the overall model performance. We have focused on agricultural ammonia sources and have analysed both hourly and daily patterns of ammonia emissions and concentrations at measurement sites located in agricultural areas or influenced by this activity. For selected episodes, we have also investigated the 3-D patterns of the ammonia concentrations in the atmosphere. The application of the dynamic ammonia emission into the WRF-Chem model (the “DYNAMIC” simulation) results in an improvement of the modelled daily ammonia concentrations in comparison to a static approach (the “BASE” simulation), which is currently widely used in chemical transport models. In the case of hourly resolution, we have observed an improvement for the DYNAMIC approach for the winter and autumn seasons, but for the entire year the modelled hourly ammonia peaks are shifted toward the afternoon hours if compared with measurements. This study indicates that the current description of the diurnal cycle of the ammonia concentration from fields is not accurate and more research is needed in order to improve the processes that describe the emission from fertilised fields. The results suggest that the governing processes in relation to the diurnal cycle are the atmospheric mixing and the emission strength. Therefore,an improved description of the diurnal profile of ammonia concentrations within atmospheric models requires a better description of the planetary boundary layer height and a stronger daily pattern of ammonia emission, e.g. through increased evaporation or increased fluxes from the surface

Road salt emissions: A comparison of measurements and modelling using the NORTRIP road dust emission model

AbstractDe-icing of road surfaces is necessary in many countries during winter to improve vehicle traction. Large amounts of salt, most often sodium chloride, are applied every year. Most of this salt is removed through drainage or traffic spray processes but a certain amount may be suspended, after drying of the road surface, into the air and will contribute to the concentration of particulate matter. Though some measurements of salt concentrations are available near roads, the link between road maintenance salting activities and observed concentrations of salt in ambient air is yet to be quantified. In this study the NORTRIP road dust emission model, which estimates the emissions of both dust and salt from the road surface, is applied at five sites in four Nordic countries for ten separate winter periods where daily mean ambient air measurements of salt concentrations are available. The model is capable of reproducing many of the salt emission episodes, both in time and intensity, but also fails on other occasions. The observed mean concentration of salt in PM10, over all ten datasets, is 4.2 μg/m3 and the modelled mean is 2.8 μg/m3, giving a fractional bias of −0.38. The RMSE of the mean concentrations, over all 10 datasets, is 2.9 μg/m3 with an average R2 of 0.28. The mean concentration of salt is similar to the mean exhaust contribution during the winter periods of 2.6 μg/m3. The contribution of salt to the kerbside winter mean PM10 concentration is estimated to increase by 4.1 ± 3.4 μg/m3 for every kg/m2 of salt applied on the road surface during the winter season. Additional sensitivity studies showed that the accurate logging of salt applications is a prerequisite for predicting salt emissions, as well as good quality data on precipitation. It also highlights the need for more simultaneous measurements of salt loading together with ambient air concentrations to help improve model parameterisations of salt and moisture removal processes

Spatial and temporal variations in ammonia emissions – a freely accessible model code for Europe

Deriving a parameterisation of ammonia emissions for use in chemistry-transport models (CTMs) is a complex problem as the emission varies locally as a result of local climate and local agricultural management. In current CTMs such factors are generally not taken into account. This paper demonstrates how local climate and local management can be accounted for in CTMs by applying a modular approach for deriving data as input to a dynamic ammonia emission model for Europe. Default data are obtained from information in the RAINS system, and it is demonstrated how this dynamic emission model based on these input data improves the NH<sub>3</sub> calculations in a CTM model when the results are compared with calculations obtained by traditional methods in emission handling. It is also shown how input data can be modified over a specific target region resulting in even further improvement in performance over this domain. The model code and the obtained default values for the modelling experiments are available as supplementary information to this article for use by the modelling community on similar terms as the EMEP CTM model: the GPL licencse v3

Improved modelling of atmospheric ammonia over Denmark using the coupled modelling system DAMOS

A local-scale Gaussian dispersion-deposition model (OML-DEP) has been coupled to a regional chemistry-transport model (DEHM with a resolution of approximately 6 km × 6 km over Denmark) in the Danish Ammonia Modelling System, DAMOS. Thereby, it has been possible to model the distribution of ammonia concentrations and depositions on a spatial resolution down to 400 m × 400 m for selected areas in Denmark. DAMOS has been validated against measured concentrations from the dense measuring network covering Denmark. Here measured data from 21 sites are included and the validation period covers 2–5 years within the period 2005–2009. A standard time series analysis (using statistic parameters like correlation and bias) shows that the coupled model system captures the measured time series better than the regional- scale model alone. However, our study also shows that about 50% of the modelled concentration level at a given location originates from non-local emission sources. The local-scale model covers a domain of 16 km × 16 km, and of the locally released ammonia (NH<sub>3</sub>) within this domain, our simulations at five sites show that 14–27% of the locally (within 16 km × 16 km) emitted NH<sub>3</sub> also deposits locally. These results underline the importance of including both high-resolution local-scale modelling of NH<sub>3</sub> as well as the regional-scale component described by the regional model. The DAMOS system can be used as a tool in environmental management in relation to assessments of total nitrogen load of sensitive nature areas in intense agricultural regions. However, high spatio-temporal resolution in input parameters like NH<sub>3</sub> emissions and land-use data is required

Characteristics and Long-term Prognosis of Danish Patients With Varicella Zoster Virus Detected in Cerebrospinal Fluid Compared With the Background Population

BACKGROUND: Risk factors for, and long-term outcomes following, detection of varicella zoster virus (VZV) DNA in the cerebrospinal fluid (CSF) are unknown.METHODS: We performed a nationwide population-based cohort study of all Danish residents who had VZV DNA detected in the CSF by polymerase chain reaction (PCR) between 1 January 1997 and 1 March 2016 (VZV cohort; n = 517) and an age- and sex- matched comparison cohort from the general Danish population (n = 9823). We examined potential risk factors and mortality, neurologic morbidity, psychiatric morbidity, redemptiom of prescriptions for nervous system medicine prescribed for the nervous system, and social outcomes.RESULTS: Prior hospital admission, redemption of immunosuppressive medicine, comorbidity, and immunosuppressive conditions were associated with detection of VZV DNA in the CSF. Mortality was increased in the VZV cohort, especially during the first year of observation and among patients with encephalitis. Patients in the VZV cohort had an increased risk of dementia and epilepsy. The redemption of antiepileptics and antidepressants was increased in the VZV cohort.CONCLUSIONS: Immunosuppression and comorbidity are associated with increased risk of detection of VZV DNA in the CSF and the condition is associated with increased mortality and neurological morbidity.</p

Plakoglobin is a mechanoresponsive regulator of naive pluripotency

Biomechanical cues are instrumental in guiding embryonic development and cell differentiation. Understanding how these physical stimuli translate into transcriptional programs will provide insight into mechanisms underlying mammalian pre-implantation development. Here, we explore this type of regulation by exerting microenvironmental control over mouse embryonic stem cells. Microfluidic encapsulation of mouse embryonic stem cells in agarose microgels stabilizes the naive pluripotency network and specifically induces expression of Plakoglobin (Jup), a vertebrate homolog of β-catenin. Overexpression of Plakoglobin is sufficient to fully re-establish the naive pluripotency gene regulatory network under metastable pluripotency conditions, as confirmed by single-cell transcriptome profiling. Finally, we find that, in the epiblast, Plakoglobin was exclusively expressed at the blastocyst stage in human and mouse embryos - further strengthening the link between Plakoglobin and naive pluripotency in vivo. Our work reveals Plakoglobin as a mechanosensitive regulator of naive pluripotency and provides a paradigm to interrogate the effects of volumetric confinement on cell-fate transitions

Long-Term Survival, Morbidity, Social Functioning and Risk of Disability in Patients with a Herpes Simplex Virus Type 1 or Type 2 Central Nervous System Infection, Denmark, 2000-2016

Background: The long-term prognosis following herpes simplex virus (HSV) central nervous system (CNS) infection is still debated. Patients and Methods: We examined outcomes in all Danish residents who, during 2000–2016, tested PCR positive for HSV-1 (n=208) or HSV-2 (n=283) in the cerebrospinal fluid, compared to comparison cohorts from the general population (n=2080 and n=2830). Results: One-year mortality was increased among HSV-1 patients (difference 19.3%; 95% CI: 13.6% to 25.0%) and HSV-2 patients (difference 5.3%; 95% CI: 2.5% to 8.1%), but thereafter mortality was not increased. After exclusion of persons diagnosed with cancer prior to study inclusion, one-year mortality difference for HSV-2 patients was 1.7% (−0.1% to 3.5%). After five years, HSV-1 patients had lower employment (difference −19.8%; 95% CI: −34.7% to −4.8%) and higher disability pension rates (difference 22.2%; 95% CI: 8.4% to 36.0%) than the comparison cohort, but similar number of inpatient days, outpatient visits, and sick leave. HSV-2 patients had employment and disability pension rates comparable to the comparison cohort, but more inpatient days (difference 1.5/year; 95% CI: −0.2 to 3.2), outpatient visits (difference 1.3/year; 95% CI: 0.3 to 3.2), and sick leave days (difference 9.1/ year; 95% CI: 7.9 to 10.4). Conclusion: HSV-1 and HSV-2 CNS infections differ substantially with respect to prog-nosis. HSV-1 CNS infection is followed by increased short-term mortality and long-term risk of disability. HSV-2 CNS infection has no substantial impact on mortality or working capability but is associated with increased morbidity.</p

Konsekvenser for emissioner og luftkvalitet af tiltag på transportområdet i Regeringens klima- og luftudspil

Regeringens klima- og luftudspil (”Sammen om en grønnere fremtid”) indeholder en beskrivelse af 38 initiativer rettet mod at reducere udledningen af drivhusgasser og/eller luftforurening. DCE - Nationalt Center for Miljø og Energi under Aarhus Universitet har gennemgået de 38 initiativer med henblik på en vurdering af hvilke af disse initiativer, der har indflydelse på luftforureningen i 2030, samt den forventede størrelse af den reducerende effekt. DCE har kvantificeret effekten af følgende initiativer og benævnt det klimascenariet: (1) Stop for salg af nye benzin- og dieselbiler i 2030 og for nye plug-in hybridbiler fra 2035, (2) Slut med udledning af CO2 og luftforurening fra busser i byerne fra 2030, (3) Benzin og diesel skal ud af taxidriften inden 2030, (4) Gamle brændeovne skrottes ved ejerskifte, og (5) Skrotpræmie til gamle brændeovne. Artiklen fokuserer på de tre virkemidler rettet mod vejtransportsektoren og sammenligner med den eksisterende basisemissionsfremskrivning for vejtrafik i Danmark i 2030, og effektvurderer scenarierne mht. til emission og luftkvalitet.&nbsp; Den største emissionsbesparelse opnås i Scenarie 1 (1 mio. elbiler), og emissions-reduktionerne for hele vejtrafikken i 2030 bliver på hhv. 13 %, 17 % og 2,1 % for NOx, PM2,5–udstødning og PM2,5–samlet (udstødning og ikke-udstødning). Hvis alle tre scenarier indføres bliver emissionsreduktionerne for NOx og PM2,5 –udstødning og PM2,5 –samlet (udstødning og ikke-udstødning) hhv. 15 %, 19 % og 2,3 %.&nbsp; Effekten af klimascenariet er vurderet for luftkvaliteten på 98 gader i København i 2030 ved beregninger af ændringer i den regionale baggrund, bybaggrund og gadekoncentrationer. Basisudviklingen fra 2016 til 2030 viser et stort fald i koncentrationerne, og klimascenariet bidrager til et yderligere mindre fald. Effekten af klimascenariet for reduktion af NO2 gadekoncentrationerne er især bestemt af reduktionen i trafikkens emissioner, mens de mindre reduktioner af PM2,5 og PM10 i højere grad er bestemt af reduktioner i emissioner fra brændeovne end fra trafik.&nbsp